If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You will be required to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Slabs & Radiant

07-12-2009, 01:44 PM

When working on a slab-on-grade resident with radiant heat, would it be a good idea to run the hot potable water above the insulation barrier and the cold potable water below the insulation barrier? This is what I thunk up and was wondering others' experience & ideas.

Comment

So what are you thunking there JC? That the cold water will pick up heat from the radiant as it moves through the slab? Some maybe, but not much, if the hot and cold are insulated as they should be underslab. Might be a little warm the first few seconds.

Comment

So what are you thunking there JC? That the cold water will pick up heat from the radiant as it moves through the slab? Some maybe, but not much, if the hot and cold are insulated as they should be underslab. Might be a little warm the first few seconds.

New house, engineer, very into DIY and from my conversation with him, screwing some things up.

Ex. At another house elected to use a Bosch Tankless and some 3/8" PEX lines for a radiant system that still gives "some problems".

I'd be in charge of the plumbing, NOT the radiant system. I'm thinking that something will get messed up in the circulation or something and yes, migration to the CW line. Happened to someone I know.

Insulating waterlines underslab-don't want to say never, but almost never done here. I've never seen it myself.

I was thinking that putting the HW in the radiant thermal mass would help when a tankless is used also. Only in winter of course. Rest of the time, normal tankless delays.

And putting the CW under the radiant/slab would eliminate any migration or blame when they screw up something involving the radiant/potable connections.